docs/doxygen/overviews/filesystem.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        filesystem.h
   3 // Purpose:     topic overview
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10
  11 @page overview_fs wxFileSystem Overview
  12
  13 The wxHTML library uses a @b virtual file systems mechanism
  14 similar to the one used in Midnight Commander, Dos Navigator,
  15 FAR or almost any modern file manager. It allows the user to access
  16 data stored in archives as if they were ordinary files. On-the-fly
  17 generated files that exist only in memory are also supported.
  18
  19 @li @ref overview_fs_classes
  20 @li @ref overview_fs_locations
  21 @li @ref overview_fs_combined
  22 @li @ref overview_fs_wxhtmlfs
  23 @li @ref overview_fs_init
  24
  25
  26 <hr>
  27
  28
  29 @section overview_fs_classes Classes
  30
  31 Three classes are used in order to provide virtual file systems mechanism:
  32
  33 @li The wxFSFile class provides information
  34     about opened file (name, input stream, mime type and anchor).
  35 @li The wxFileSystem class is the interface.
  36     Its main methods are ChangePathTo() and OpenFile(). This class
  37     is most often used by the end user.
  38 @li The wxFileSystemHandler is the core
  39     of virtual file systems mechanism. You can derive your own handler and pass
  40     it to the VFS mechanism. You can derive your own handler and pass it to
  41     wxFileSystem's AddHandler() method. In the new handler you only need to
  42     override the OpenFile() and CanOpen() methods.
  43
  44
  45 @section overview_fs_locations Locations
  46
  47 Locations (aka filenames aka addresses) are constructed from four parts:
  48
  49 @li @b protocol - handler can recognize if it is able to open a
  50     file by checking its protocol. Examples are "http", "file" or "ftp".
  51 @li <b>right location</b> - is the name of file within the protocol.
  52     In "http://www.wxwidgets.org/index.html" the right location is "//www.wxwidgets.org/index.html".
  53 @li @b anchor - an anchor is optional and is usually not present.
  54     In "index.htm#chapter2" the anchor is "chapter2".
  55 @li <b>left location</b> - this is usually an empty string.
  56     It is used by 'local' protocols such as ZIP.
  57     See Combined Protocols paragraph for details.
  58
  59
  60 @section overview_fs_combined Combined Protocols
  61
  62 The left location precedes the protocol in the URL string.
  63
  64 It is not used by global protocols like HTTP but it becomes handy when nesting
  65 protocols - for example you may want to access files in a ZIP archive:
  66 file:archives/cpp_doc.zip#zip:reference/fopen.htm#syntax
  67 In this example, the protocol is "zip", right location is
  68 "reference/fopen.htm", anchor is "syntax" and left location
  69 is "file:archives/cpp_doc.zip".
  70
  71 There are @b two protocols used in this example: "zip" and "file".
  72
  73
  74 @section overview_fs_wxhtmlfs File Systems Included in wxHTML
  75
  76 The following virtual file system handlers are part of wxWidgets so far:
  77
  78 @li @b wxArchiveFSHandler:
  79     A handler for archives such as zip
  80     and tar. Include file is wx/fs_arc.h. URLs examples:
  81     "archive.zip#zip:filename", "archive.tar.gz#gzip:#tar:filename".
  82 @li @b wxFilterFSHandler:
  83     A handler for compression schemes such
  84     as gzip. Header is wx/fs_filter.h. URLs are in the form, e.g.:
  85     "document.ps.gz#gzip:".
  86 @li @b wxInternetFSHandler:
  87     A handler for accessing documents
  88     via HTTP or FTP protocols. Include file is wx/fs_inet.h.
  89 @li @b wxMemoryFSHandler:
  90     This handler allows you to access
  91     data stored in memory (such as bitmaps) as if they were regular files.
  92     See wxMemoryFSHandler for details.
  93     Include file is wx/fs_mem.h. URL is prefixed with memory:, e.g.
  94     "memory:myfile.htm"
  95
  96 In addition, wxFileSystem itself can access local files.
  97
  98
  99 @section overview_fs_init Initializing file system handlers
 100
 101 Use wxFileSystem::AddHandler to initialize a handler, for example:
 102
 103 @code
 104 #include <wx/fs_mem.h>
 105
 106 ...
 107
 108 bool MyApp::OnInit()
 109 {
 110     wxFileSystem::AddHandler(new wxMemoryFSHandler);
 111 ...
 112 }
 113 @endcode
 114
 115 */
 116